In order to prevent the line system in which washing liquor is circulated in water conducting household appliances, such as dishwashers for example, becoming contaminated with dirt particles, a filter system is used, which may comprise a coarse filter, a fine filter and a micro filter. The coarse filter here serves to retain dirt particles, which could lead to a blockage of the washing liquor pump. A fine filter retains particles with a particle size greater than approximately 1 mm and a micro filter retains particles with a particle size greater then approximately 0.15 mm.
A water conducting household appliance such as a dishwasher for example has a washing liquor pump, which can be used to convey washing liquor that is contaminated at the end of the washing operation out of the dishwasher into a house-side waste water disposal system. Such washing liquor pumps are designed so that they can convey larger particle sizes unimpeded and there is no blockage of the washing liquor pump. Washing liquor pumps are therefore disposed so that contaminated washing liquor is only filtered coarsely during the pumping operation.
A dishwasher also has a circulation pump, which can be used to circulate washing liquor during a cleaning operation; in other words fluid collecting in the pump sum of a dishwasher is fed by means of the circulation pump through a hydraulic system to spray arms disposed in the interior of the washing compartment, said spray arms then spraying washing liquor onto the items to be washed in a regular manner. The spray arms have relatively small openings so it is necessary to pass the circulated washing liquor through the fine and micro filters so that even the smallest particles are retained and the outlet openings of the spray arms cannot become blocked. The circulation pump is configured accordingly in respect of particle size tolerance.